Can any of you guys here help me out? I'm in an argument with someone I know about the existence of free will. I think that it is real and that determinism is wrong, but I'd like to know if you guys have any scientific evidence of free will existing that I could use. Sources and links would be much appreciated.

Unless stated otherwise, I do not care whether a statement, by itself, constitutes a persuasive political argument. I care whether it's true.---If this post has math that doesn't work for you, use TeX the World for Firefox or Chrome

"Free will" is generally not defined rigorously enough to be tested scientifically. If you can define it rigorously enough that you can test it, then it is usually something that is either trivially true or trivially false.

fearcypher wrote:I think that it is real and that determinism is wrong, but I'd like to know if you guys have any scientific evidence of free will existing that I could use.

Since you're mentioning determinism: Current scientific consensus is that the universe is deterministic.See the Schrödinger Equation, an equation from quantum mechanics which, given any state of the universe, allows you to calculate any past and any future state of the universe. Obviously, such an equation can only be true in a deterministic universe. And we have a lot of theoretical and experimental evidence saying that it's true.

Whether or not determinism contradicts free will depends on your definition of free will. Doogly has posted the relevant link.

fearcypher wrote:I think that it is real and that determinism is wrong, but I'd like to know if you guys have any scientific evidence of free will existing that I could use.

Since you're mentioning determinism: Current scientific consensus is that the universe is deterministic.See the Schrödinger Equation, an equation from quantum mechanics which, given any state of the universe, allows you to calculate any past and any future state of the universe. Obviously, such an equation can only be true in a deterministic universe. And we have a lot of theoretical and experimental evidence saying that it's true.

Whether or not determinism contradicts free will depends on your definition of free will. Doogly has posted the relevant link.

Not even close. All experimental data and theory from quantum mechanics, at least in the most popular "interpretations" point directly towards the universe being fundamentally random (within the defined yada yada etc.) The most important confirmation of this, Bell's theorem, and experiments, do indeed seem to point directly to the universe being truly random at its base level. https://en.wikipedia.org/wiki/Bell's_theorem

Admittedly it points at an odd, highly correlated "randomness" wherein a quantum measurement, say the spin of an electron, is both random and somehow directly correlated to a subsequent entangled spin. The spins of both electrons should be "random" and yet once you measure and know the spin of either electron, if they're entangled, then you know the spin of the other, AKA Einstein's "spooky action at a distance". And indeed this rubs a lot of physicists the wrong way. It definitely "feels" like somehow this should indicate the outcome of the measurement isn't random, because how can two things be "random" in the exact same way? But so far no one's been able to pin down any concrete mathematical or physical reasoning as to why it isn't random, and Bell's strongly suggests it is.

So, yes, insofar as established scientific theory goes randomness is "Real". Whether this means your idea of "free will" is also real depends entirely on how you define free will. After all, how is a bunch of random outcomes anymore encouraging than the idea of no randomness? The very term "free will" seems a bit of an oxymoron, "will" indicating intent and determism, "free" indicating randomness and chaos. But I'll leave that up to you to decide.

Yes, quantum things are probabilistic in nature, so you have an appearance of randomness in measurements. That does not contradict the deterministic evolution of the underlying quantum states (including all its probabilities).

The only interpretation with non-determinism is the copenhagen interpretation, and the only non-deterministic event is the wave function collapse, which (to put it mildly) still remains a problematic and poorly defined concept. With many-worlds, all of the random outcomes do happen, so there's no actual randomness - it just appears that way from the point of view of someone trapped in one split of the wavefunction.

Tub wrote:Yes, quantum things are probabilistic in nature, so you have an appearance of randomness in measurements. That does not contradict the deterministic evolution of the underlying quantum states (including all its probabilities).

The only interpretation with non-determinism is the copenhagen interpretation, and the only non-deterministic event is the wave function collapse, which (to put it mildly) still remains a problematic and poorly defined concept. With many-worlds, all of the random outcomes do happen, so there's no actual randomness - it just appears that way from the point of view of someone trapped in one split of the wavefunction.

Copenhagen is the most used, accepted, and "standard" interpretation out there. Other interpretations are mostly considered semantics at best. Many worlds is "what if there's an infinite exponential amount of worlds that never interact otherwise and you can never prove and makes no concrete predictions whatsoever but it feels better because radomness isn't real!". Kind of thing. IE it's basically arguing philosophy at that point.

So, like I said, as far as the most popular (and simple and direct) interpretation of quantum mechanics goes, randomness is perfectly real. Sure, superdeterminism or many worlds or etc. could be real, randomness could be false, the universe could be perfectly deterministic. But God could be real, or Thor or Eru Ilúvatar or whatever other all powerful diety. You can't disprove it, and the universe should come from somewhere right? Point is, you can never really "prove" anything is "truly" real and the truth and etc. other than the fact of your own existence (cogito ergo sum). But the point of science is to do our best (or, your best?) anyway, and the generally accepted "best" at the moment is that randomness exists.

Now if someone, anyone, could offer physical evidence otherwise; something beyond an "interpretation", or maybe even a simpler and more direct interpretation than Copenhagen, then everyone (most everyone) would be all ears. But for now copenhagen "the standard" if only because most agree that it should be. Not the best way to set a standard, but lacking anything any better way it'll have to do for now.

In any case, randomness doesn't get you free will either, so it's not like Frenetic Pony's point rescues the OP's position.

Unless stated otherwise, I do not care whether a statement, by itself, constitutes a persuasive political argument. I care whether it's true.---If this post has math that doesn't work for you, use TeX the World for Firefox or Chrome

Also, Frenetic Pony is thinking of a "Fundamental Collapse" flavor of Copenhagen, in which the collapse actually breaks deterministic evolution and has some real meaning. This is by no means a standard and widely used interpretation. It is ultra weird. Generally we only speak of collapse in a coarse grained sense, in which a "Born cut" can be made between the quantum system and a measuring device. But it is understood that under the covers, it's all just nice unitary deterministic evolution, but with lots of decoherence going on.

LE4dGOLEM: What's a Doug?Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.

Frenetic Pony wrote:Copenhagen is the most used, accepted, and "standard" interpretation out there. Other interpretations are mostly considered semantics at best. Many worlds is "what if there's an infinite exponential amount of worlds that never interact otherwise and you can never prove and makes no concrete predictions whatsoever but it feels better because radomness isn't real!". Kind of thing. IE it's basically arguing philosophy at that point.

Copenhagen makes the uncomfortable prediction of non-determinism, thus people prefer outrageous and untestable band-aids like many worlds to avoid it.Many-worlds make the uncomfortable prediction of multiple existances, thus people prefer outrageous and untestable band-aids like wave function collapse to avoid it.

The emotional argument can be made either way, but it doesn't tell us anything about the universe. Can we just agree that quantum mechanics makes *everyone* uncomfortable?

The simple and direct interpretation of the schrödinger equation is the evolution of the wave function into many decoherent parts. You can call those non-interacting parts of the wavefunction "worlds" if you like; there are certainly many of them.Now you can say that you're only interested in a theory about your own life, and you don't want to care about the parts of the wave function that don't affect you. So you introduce a wave function collapse that gets rid of all the decorrelated states and normalizes the remaining ones. You still make the same predictions about yourself - after all, you only removed the parts that don't affect you - so it's a perfectly valid theory without any testable differences.

But if you want to argue that the universe is non-deterministic, then you must prove that the wave function collapse is not merely an interpretation or bookkeeping trick, but an actual physical event, and that the decorrelated parts don't just disappear from our own view, but stop existing entirely. You'll need to solve the measurement problem and prove a fundamental (non-entropic) arrow of time in the direction of the non-reversable collapse. For that, the burden of proof is on you, not on me, and I don't think many reputable physicists will agree with you.

madaco wrote:So, is it just me not understanding, or does many worlds seem rather like modal realism?

Not really. It sort of depends on how you interpret the wave function to begin with. In MWI, the wave function is the real object; particles are just almost asymptotically pointlike parts of the wavefunction which are incoherent with every other part. That's what it means to say that a particle is at a particular place. But of course, there are particles at other locations too, we just cannot (practically) observe them, because they are so incoherent.

MWI is actually not outrageous at all. It simply takes Schrodinger's equation at face value and makes no additional assumptions. If no objective collapse occurs, then decoherence alone does still produce the observed results, but also implies the troubling fact that the universal wave function (if it exists) is split into a colossal number of incoherent parts (which it calls "worlds") which have practically no interaction with each other, and therefore are effectively unobservable.

If you think about it as "modal realism," that's probably because you are considering Born's Law, which assigns a probability to every eigenvalue of each observable. In this sense, it does sort of make sense to say that every possible measurement happens, and Born's Law gives the fraction of all worlds in which the observable takes on each eigenvalue. This is however different from proper modal realism, in which every logically contingent statement is true in some world.

Flumble wrote:My lack of free will makes me think I choose to believe in free will.

Unless stated otherwise, I do not care whether a statement, by itself, constitutes a persuasive political argument. I care whether it's true.---If this post has math that doesn't work for you, use TeX the World for Firefox or Chrome

Ignorance gives you free will in a deterministic universe. You make decisions and act based on the incomplete information you are able to obtain. The universe may be deterministic, but information about its course is not available to you. If you always knew the best action according to your motives, you would not have free will. You do have free will, because ignorance. Under this definition.

(This is analogous to St. Augustine's attempt to construct free will for humans under an omniscient and omnipotent God; God sees the universe all at once "totum simul", but that perspective is not available to humans. However, I do not wish to continue the analogy since it is not terribly useful to an agnostic.)

And the universe is in fact deterministic. The performance of a classical measurement appears to introduce indeterminism, but in fact merely displays our ignorance of the initial state of the classical measurement apparatus. Can't prove it. Wish I could.

The fact that you don't know what you're going to choose doesn't mean your choice is free in any satisfying sense of the word.

Unless stated otherwise, I do not care whether a statement, by itself, constitutes a persuasive political argument. I care whether it's true.---If this post has math that doesn't work for you, use TeX the World for Firefox or Chrome

doogly wrote:And I throw these links out there like pearls before swine.

Take solace in the many worlds interpretation, and know that somewhere, in some remote part of the wavefunction, someone actually clicked your link. Most certainly not in *your* part of the wavefunction, but somewhere.

gmalivuk wrote:The fact that you don't know what you're going to choose doesn't mean your choice is free in any satisfying sense of the word.

I honestly think it does, but that just goes back to LaserGuy's response that "free will" is too poorly defined to argue about in this sense. Because at that point, it really is a question of whether or not you find the known reality subjectively satisfying.

So much depends upon a red wheel barrow (>= XXII) but it is not going to be installed.

gmalivuk wrote:As I said upthread, adding randomness doesn't get you free will.

If nothing is random, there can be no free will, because everything is preordained from initial conditions.

So randomness must at least "allow" free will, its a condition for its presence.

Is there anything wrong with those 2 statements?

Free will, if it exists in a strong philosophical sense, would have to involve something that is neither preordained from initial conditions nor random.The occasional bit of randomness might make things look more free from the outside, but I don't see how there's any actual freedom there.

How much difference is there between, "You must do A," and, "You must do A if this coin lands on heads, and you must do B if it lands on tails"?

Unless stated otherwise, I do not care whether a statement, by itself, constitutes a persuasive political argument. I care whether it's true.---If this post has math that doesn't work for you, use TeX the World for Firefox or Chrome

Only that there certainly cant be free will in a deterministic, non-random universe.

So it could be said that: No randomness rules out free will.

Therefore, the presence of randomness, if it can be shown, to me says that free will is a possibility.

That is not to say that it cannot be ruled out due to some other factor.

***

The more I think about it, the more a meaningful definition of "free will" eludes me. This makes this question very difficult. The above statements are about the only clear thing I can conceive on the matter.

The irony of having a discussion on the nature of free will in what could very well be a free-will-free universe, is quite satisfying however.

p1t1o wrote:I dont mean to draw a comparison between "free will" and randomness.

Only that there certainly cant be free will in a deterministic, non-random universe.

So it could be said that: No randomness rules out free will.

My point is, no, this cannot be concluded from the fact that complete determinism rules out free will. If free will requires some third thing, then the balance of randomness and determinism doesn't tell us anything about it.

1) There certainly can't be water on a hydrogen-only, helium-free planet.2) So it could be said that: No helium rules out water.

The second statement does not follow from the first.

Unless stated otherwise, I do not care whether a statement, by itself, constitutes a persuasive political argument. I care whether it's true.---If this post has math that doesn't work for you, use TeX the World for Firefox or Chrome

p1t1o wrote:I dont mean to draw a comparison between "free will" and randomness.

Only that there certainly cant be free will in a deterministic, non-random universe.

So it could be said that: No randomness rules out free will.

My point is, no, this cannot be concluded from the fact that complete determinism rules out free will. If free will requires some third thing, then the balance of randomness and determinism doesn't tell us anything about it.

1) There certainly can't be water on a hydrogen-only, helium-free planet.2) So it could be said that: No helium rules out water.

The second statement does not follow from the first.

I dont follow, are you saying that free will could exist in a deterministic universe?

Free will would require something other than determinism or randomness, just like water requires something other than hydrogen or helium.

Therefore, the presence of randomness no more allows for free will than the presence of helium allows for water.

Unless stated otherwise, I do not care whether a statement, by itself, constitutes a persuasive political argument. I care whether it's true.---If this post has math that doesn't work for you, use TeX the World for Firefox or Chrome

Or like, if you are wondering if there is a yellow marble in a bag, and someone tries to reassure you by saying "It's not just red marbles in there! Also blue!" they are a useless person and you should unfriend them.

LE4dGOLEM: What's a Doug?Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.

p1t1o wrote:I dont mean to draw a comparison between "free will" and randomness.

Only that there certainly cant be free will in a deterministic, non-random universe.

Why not, though?

If by "free will" you mean that something outside causality should reach in, override your history/knowledge/proclivities/desires, and make the decision for you - then sure, determinism means no "free will". But that doesn't seem much like freedom.

It seems to me defensible to say that decision processes in a deterministic universe can be free, or that the idea of free will is incoherent, but not that freedom requires randomness.

No, even in theory, you cannot build a rocket more massive than the visible universe.

The typical notion of free will is tied to the idea of a soul, or a mind separate from the body. If it's the body itself making the choice (as it is in a deterministic universe), then you need an awful lot of bending to still call that free. What most people mean by free will does require that "something outside causality". The only way around that is to start arguing definitions (like how I can obviously still make choices despite those choices being predetermined), but that's not as interesting, even if it is satisfying in its own way.

It's worth mentioning that quantum randomness is probably not going to be a particularly significant effect in the macro-level interactions that happen in the brain. It's too big, there's too many particles, and it's too hot.

What is more likely to be significant is that a lot of the systems that we care about when we talk about free will are chaotic (in the mathematic sense): even slight changes in the initial conditions may have profound effects on the progression over time. So even though, say, the function of the human brain is completely governed by the laws of physics, it may be sufficiently sensitive to environmental conditions that it may be impossible to deterministically say how it will react in any given situation.

[edit]Or, more precisely, it may be that it is impossible to specify the conditions of the brain to sufficiently high precision to be able to deterministically predict its response to a given stimulus.